Generally, an electronic timepiece such as a wristwatch comprises a case that includes an electronic circuit controlling the display means to display information on a dial. The dial is made in the form of a plate having, on the side of its display face, decorative elements, indices, and/or markings representing for example the numbers of the hours. The dial can also comprise a window associated with a liquid crystal screen connected to the electronic circuit. The dial is usually made of plastic material or metal.
The electronic control circuit is generally arranged on a printed circuit board (PCB) and it includes electronic components such as a control unit, conductive paths, and a reference oscillator which acts as a time base. The oscillator includes a resonator, for example a quartz resonator.
Some watches do not have a PCB. The electronic components are then mounted directly on the back cover of the case. The conductive paths are made, for example, in the form of metallic strips fixed in the case.
The watch structures that have just been described are not completely satisfactory since they require numerous assembly operations, particularly for mounting each of the electronic components either on the PCB, or in the back cover of the case. Moreover, the space requirement of these electronic components in the case is inconvenient when one wishes to make the watch more compact, particularly the thickness thereof.
There also exist watch dials made in a crystalline material such as silicon. Thus, U.S. Pat. No. 4,599,251 discloses and shows a decorative watch article made of silicon. The dial includes a top layer, for example of silicon dioxide, which is light permeable and allows coloured interferences to be formed at its surface. Further, decorative designs or indices can be made on the top surface of the dial, from an opaque material, by printing or vapour phase deposition.
This type of dial has an aesthetic advantage but the general structure of the watch is not altered and still has the same drawbacks.
It is an object of the invention to overcome these drawbacks.